Vibrating refractory furnace



United States Patent 72] lnventor John Mitchell San Pedro, California [21 Appl. No. 629,273 [22] Filed April 7, 1967 [45] Patented Nov. 10, 1970 [73] Assignee John Mitchell Corporation San Pedro, California a corporation of Delaware [54] VlBRATING REFRACTORY FURNACE 17 Claims, 3 Drawing Figs.

[52] U.S. Cl 263/21, 75/63: 263/27; 266/33 [51] Int. Cl F27b 3/00 [50] Field ofSearch 263/2 KC). 27; 266/33; 75/63 [5 6] References Cited UNITED STATES PATENTS 1,899,031 2/1933 Hanak 75/63X 1,938,239 12/1933 White 266/33 2,531,975 11/1950 EssexetaL. 263/2i(C) 2,734,244 2/1956 l'lelleS 266/33x 2,845,261 7/1958 Furczyk 263/27 Primary Examiner.lohn J Camby Attorney- Lyon and Lyon ABSTRACT: A furnace for the controlled heating at any temperature of materials continuously passing therethrough where the hearth is an inclined platform of refractory material supported in a superstructure that is flexibly mounted and subjected to controlled vibration whereby materials continually introduced onto the upper end of the inclined refractory platform progress at a controlled rate toward the lower end where all the unmelted and unvaporized materials are continually discharged and the melted material is tapped off within the furnace. The heating unit issuperimposed immediately above the hearth and extends the length and width of the hearth for controlled heating therealong and the heating unit is removable as a unit for access to the hearth for maintenance.

VIBRATING REFRACTORY FURNACE This invention relates in general to an improved furnace apparatus adapted to continuously pass any material therethrough under controlled heating to any desired temperature for any duration. The apparatus is particularly useful for separating and recovering metals and alloys by heat treatment and agitation, and herein is so described. Thus more the invention relates to a refractory furnace adapted to continuously separate certain fusible metals and alloys by sweating same out from their union with less fusible metals and alloys. In operation, the invention, among other things, continuously advances a succession of metallic material, which may previously be broken into small pieces, into a heated chamber so as to cause the metals or alloys having a lower melting point to separate by melting and agitation from those having a substantially higher melting point.

Various devices and methods have heretofore been employed for producing the sweating of metals and alloys having substantially different temperatures of fusion. For instance, a common practice has been to place the metallic material to be separated into an oven or retort and subject same to a great amount of heat so that the more fusible metal or metal alloy melts and drops into a receiver or tray beneath the oven or retort while the less fusible metal or metal alloy is mechanically removed from the container. However, this method is extremely limited in that a substantial amount of time is necessary to operate the device, thus making it not practical for large scale separation. Further, contamination of the melt is likely. Other devices utilized for such separation cause the recovered metals to become oxidated by directly heating the metallic material, or are not of a continuous process. In addition the prior art furnaces comprising combustion and heating chambers are integral and of a unitary design so that if a portion thereof is defective, it is extremely costly and time consuming to repair same due to the entire furnace being required to be dismantled. It is also known that many unitary furnaces are caused to vibrate, causing unre lieved stresses throughout the apparatus. Still other furnaces have employed vibrating pans therein for causing the desired agitation and advancement of the material therethrough but these are limited to very low temperature applications due to the presence of the pans and vibrating apparatus. As may therefore be appreciated, such prior art devices have many drawbacks, and the sweating of metals and alloys by such devices as described above is not being practiced by any steel producer or scrap dealer.

Accordingly, by this invention there is provided a novel form of continuous furnace adapted for virtually all temperatures wherein an inclined refractory hearth supports the material and is vibrated for causing progression of the material through the furnace.

It is a particular object ol'the present invention to provide a simple apparatus whereby metals and metal alloys can be treated by the judicious application of radiant heat so that the metals and alloys comprising same can be separately recovered in a continuous manner.

A further object of the present invention is to produce such an apparatus as described above whereby the combustion chamber and the melting chamber are adjacent to each other, yet separated by thin heat conductive material, so that among other things the objectionable effects of oxidation in the recovered metals and alloys are practically eliminated.

Another object of the present invention is to provide a chamber for the melting of metals or alloys having a relatively low temperature of fusion intermixed with metals having a relatively higher temperature of fusion, whereby the conveyor platform thereof is adapted to be vibrated and selectively sloped so that the scrap metal material flows downwardly within said chamber in a controlled manner.

A further object of the present invention is to provide a furnace as mentioned above whereby the conveyor platform is raised along its longitudinal axis so that the molten metal runs along the edges thereof and is not contaminated by the.

remaining solid metals.

An additional object of the present invention is to provide a refractory furnace as mentioned above whereby its combustion and melting chambers are capable of being slidingly disengaged from each other.

Other and additional objects and advantages of the present invention include having a refractory furnace encased in an outer metal lining so that same is resistant to external vibratory forces being placed thereon, and to provide a sturdy apparatus which is very simple and economical to manufacture, assemble and use, and which may be easily separated into its major component parts so that repairs can be conducted on any portion thereof without disturbing the remainder of said apparatus, and such objects, advantages and capabilities will be readily apparent and better understood from the following description, taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a partial cross-sectional view of the invention;

FIG. 2 is a cross-sectional view of the wall and floor construction of the melting chamber taken along lines 22 of FIG. I; and

FIG. 3 is a longitudinal cross-sectional view of the invention taken along lines 3-3 of FIG. 1.

Referring to the'drawing in detail, the refractory furnace is shown generally as 10 and comprises two major portions, namely: a combustion chamber shown generally as 11 and a melting chamber shown generally as 12. While the apparatus will be particularly described in connection with its use in separating low melting point metals from scrap metal material of both low and high melting points, it is to be understood and will readily appear to those skilled in the art that this furnace apparatus has a great may uses and may employ a wide range of temperatures.

The said melting chamber 12 consists of a substantially elongated U-shaped body of ceramic or refractory material, and the sides, 18a and 18b, and platform base thereof may conveniently be developed by a multiplicity of successive layers of refractory if desired, with the refractory bricks 19 of each such layer being arranged in a tongue-and-groove manner for purposes hereinafter discussed. A thin metal or housing 20 encloses the exterior of said sides 18a and 18b and base 18c, and the side members 20a and 20b thereof are canted inwardly from the base lining 200 so that said refractory bricks 19 will remain permanently in place and not pull or fall out due to stresses created by periodic vibrations and the charge of scrap metal material 14 being conveyed within said melting chamber 12. The platform base 18c is elevated at one end 15 thereof, and the center portion 21 is pitched upwards or crowned along its longitudinal axis.

Said melting chamber 12 is permanently but flexibly supported on a series of pliable mounts 22, which are adapted to support said chamber 12 even when the same is vibrated in the manner hereinafter discussed. Standard vibrating means 23 is suitably affixed to the underside or any other convenient portion of said melting chamber 12, and is adapted to continuously strike same so as to cause periodic vibrations having a small amplitude but a high frequency in said platform 18c. Variable controls may be introduced with said means 23 so that both the frequency and amplitude of the vibrations are altered to the requirements of the scrap metal charge 14, whereby, as is well known to those skilled in the art, the rate at which the material progresses through the furnace may be controlled.

A hopper 13 is suitably mounted at the elevated end of said melting chamber 12, and is adapted to continuously feed scrap metal material and the like 14 into the said chamber 12 at the higher end 15 of said platform 21.

A U-shaped'heating chamber 11 is provided with similar refractory or ceramic materials, all enclosed by metal shell 29.

As may be seen in FIG. 3 of the drawing, solid scrap metal 14 is introduced into the melting chamber 12 by said hopper 13 as aforesaid. By means of radiant heat being applied to said chamber 12, the lower melting metal or alloy begins to melt 24, and the entire charge of metallic material flows downward on said conveyor platform 180 due to the force of gravity and the continuous agitation by said vibrating means 23. The molten metal will flow in drain troughs 25a and 2512, which are provided along the sides of said platform 18c due to the pitch thereof. The width of said troughs 25a and 25b is critical in that it should be small enough so that the nonmelting metal particles 14 do not enter same. Consequently, a relatively pure melt 24 is obtained. At the lower end of said inclined platform 18c, and at each side 18a and 18b of said chamber 12, a ceramic or refractory lined drain pipe 26 is provided to convey the melt out of said chamber 12. As the scrap metal material 14 moves downwardly as aforesaid, the lower melting point metal, such as zinc or aluminum (which melt at approximately 780F. and l220F., respectively), is melted and flows from said melting chamber 12 through said pipe 26 to a collection vessel (not shown). However, the unmelted pieces 14 of the higher melting metal or alloy is conveyed directly into an adjacent collecting platform 27 for subsequent mechanical withdrawal thereof.

The said combustion chamber 11 consists of a substantially inverted U-shaped body of ceramic or refractory material, with the sides 28a and 28b and roof 286 being encased by an outer metal lining 29. A plurality of l-beams 30 are weldably affixed in parallel fashion to the said roof member 280 of said combustion chamber 11. Said l-bcams 30 are rigidly connected at each end in a perpendicular fashion to support bars 31, which are in turn journaled in bearing brackets 32 to rollers 33. Said rollers 33 are adapted to slidably or rollably engage rail members 34, which are directly parallel to the longitudinal axis of the furnace 10. As may be appreciated by viewing FIG. 1 ofthe drawing. the entire combustion chamber 11 is supported on said rail members 34, and said chamber ll may be horizontally moved thereon without any interference whatsoever with the melting chamber 12 or its several attachments. Thus by moving the chamber 11 longitudinally away from the chamber 12 access is readily gained to the interiors of both chambers for repairs and maintainance.

plurality of gas burners 35 having inlets 36 for introducing therein oxygen and a appropriate fuel mixture are placed on top of the roof of said combustion chamber 11. Upon ignition of each burner, the flames thereof pass through its associated central orifice 37, each of said orifices provided within a mounting well 38, which is set within the refractory material of said roof 280. Since conventionally the burners 35 are adjustable, the temperatures produced along the length of the combustion chamber 11 may be preselected to give the desired zones of heating along melting chamber 12. As indicated by the broken lines at the right hand end of FIG. 3, the chambers 11 and 12 may be of any preselected length to produce the necessary hcat zones and resident time, as also cffected by the slope and vibration of the hearth, to accomplish the desired heating and melting of the material 14.

in operation, the combustion chamber 11 is set above and immediately adjacent the said melting chamber 12, and is separated therefrom by a flat heat transfer member 39, which should be made from an excellent conductor of heat and have a high melting temperature. An example of such a material is silicon carbide. Obviously the separation of chambers 11 and 12 by the member 39 permits the use of a controlled atmosphere in the melting chamber 12 when desired. Further, physical contact between said chambers 11 and 12 is made at points 40 and 40a by contact with said metal linings and 29. As may be appreciated, when said melting chamber 12 is agitated by said vibrating means 23, the contact may be momentarily broken, thus permitting the escape of certain gases from the said combustion chamber 11. Consequently, U- shaped baffle plates 41 are employed, which engage the flanged area 42 of said linings 20 and 29 so as to retain the said gases within said chamber. Finally, an exhaust hood 43 is shown diagrammatically, which permits combusted gases to escape to a particular collecting and disposing area. An exhaust is also provided above the hopper so that any gases escaping through the melting chamber may be captured and disposed of.

While only one particular embodiment of the invention has been described and shown, the present invention is not intended to be restricted to any particular construction or arrangement, or to the specific embodiments disclosed herein, or to any specific method of operation, since the same may be modified in various particulars or relations without departing from the spirit or scope of the claimed invention hereinabove shown and described of which the said embodiment is intended for illustration and for disclosure of an operative embodiment, and not to show all of the various forms and modification in which the invention might otherwise be embodied.

lclaim:

1. A furnace for treating scrap metal comprising an inclined rectangularly shaped platform having a pitch along its longitudinal axis; means adapted to flexibly support said platform; means for continuously supplying said scrap metal to the elevated end of said platform; said platform being adapted to have said scrap metal conveyed downwardly thereon; means attached to said platform and adapted to periodically vibrate said platform and thus any scrap metal thereon; heating means adapted to radiantly heat said scrap metal on said platform; means adapted to slidably support said heating means; means adapted to separate molten metal from solid metals; and said platform extending beyond said separating means and said heating means for conveying such solid metals out of the furnace. I

2. A furnace for treating scrap metal comprising an inclined platform consisting of laminated layers of ceramic or refractory material, with each layer thereof being constructed in a tongue-and-groove arrangement; means to support said platform; hopper means for supplying scrap metal to the elevated end of said platform; means adapted to vibrate said platform and thus any scrap thereon; heating means in removable engagement with said platform; said heating means being adapted to heat said scrap metal on said platform; means adapted to support said heating means; means adapted to separate molten metal from solid metals; and said platform extending beyond said separating means and said heating means for conveying such solid metals out of the furnace.

3. A furnace for treating scrap metal comprising an enclosed pitched platform adapted to have said metal conveyed downwardly thereon; means for supporting said platform in a selectively inclined position; means for continuously introducing said metal onto the elevated end of said platform; means for continuously heating said metal during its decline on said platform; means adapted to separate liquid metals from solid metals within said furnace; and said platform extending beyond said separating means and said heating means for conveying such solid metals out of the furnace.

4. A furnace for treating scrap metal comprising an enclosed platform adapted to have said metal thereon fall in a downward direction; means for supporting said platform in s selectively inclined position; means for introducing said metal onto the elevated end of said platform; means removably attached to said enclosed platform and adapted to heat said metal by radiation during its decline on said platform; means adapted to segregate the liquid metals from the solid metals during their decline on said platform; and said platform extending beyond said segregating means and said heating means for conveying such solid metals out of the furnace.

5. A furnace for separating lower melting metals and alloys from higher melting metals and alloys, said furnace comprising means adapted to convey scrap metal down an inclined platform; means adapted to heat said scrap metal during its decline until the lower melting metals and alloys are melted; said heating means and platform being joined along a plane inclined in the same direction as the platform incline; said heating means supported for horizontal movement and adapted to disengage horizontally from contact with the said platform in the direction of downward inclination of said platform; and means adapted to separate said molten metals from the metals and alloys not melted in said furnace.

6. An apparatus for separating alloys and metals having substantially different melting points, said apparatus comprising a furnace; an inclined platform having walls integral therewith so as to form an elongated trough; said platform having a centrally pitched floor surface along the length thereof; means affixed to said furnace and adapted to introduce scrap metal onto the elevated end of said trough; means for periodically agitating said trough so that agitation of any material with in said trough results; means adapted to radiantly heat said scrap metal during its decline on said platform to a temperature above the melting point of a particular kind of said metals and below the melting point of the remainder of said metals; means at the lower end of said platform adapted to remove the molten metal from the furnace; platform means adjacent to said inclined platform adapted to retain the nonmolten metals; means adapted to remove said nonmolten metals from said adjacent platform means; and exhaust means adapted to remove the products of combustion from said heating means.

7. A continuous furnace for controlled heating of materials to any predetermined temperature, comprising, an inclined platform of a refractory substance forming a hearth for supporting the material to be heated, heating means positioned immediately above substantially the entire said platform for heating the material, said platform having an upper end with means for receiving the material, means flexibly supporting said platform for vibratory motion, and means for vibrating said platform for causing the material to progress down said inclined platform while being heated, and said platform having an angle of inclination preselected in relation to said material for causing ready but controlled progress of such material on said platform by said vibration.

8. The furnace of claim 7 wherein said platform is of a substantial length in the longitudinal direction of inclination compared to the lateral width thereof for allowing a wide range of control of the time the material remains in the furnace by controlling the said vibration of said platform.

9. The furnace of claim 7 wherein said heating means includes a plurality of separately controllable burners spaced therealong in the longitudinal direction of inclination for controlling the temperature to preselected levels throughout the length.

10. The furnace of claim 9 wherein said heating means includes an impervious heat transfer member separating said burners from and positioned in spaced relation to said platform for radiantly heating the material.

11. The furnace of claim 1 wherein said means for receiving the material includes an externally extending hopper into which the material is introduced, said hopper having an open lower end positioned immediately above the surface of the upper end of said platform.

12. A continuous furnace for controlled heating of materials to any predetermined temperature, comprising, an inclined platform of a refractory substance forming a hearth for supporting the material to be heated, heating means positioned immediately above substantially the entire said platform for heating the material, said heating means and said platform comprising separate integral units releaseably connected together during use of the furnace, said heating means inclined similar to said platform and movably mounted on horizontal rails extending in the direction of inclination for moving said heating means horizontally away from said platform for maintenance and repair, said platform having an upper end with means for receiving the material, means flexibly supporting said platform for vibratory motion, and means for vibrating said platform for causing the material to progress down said inclined platform while being heated.

13. A continuous furnace for controlled heating of materials to any predetermined temperature, comprising, an inclined platform of a refractory substance forming a hearth for supporting the material to be heated, heating means positioned immediately above substantially the entire said platform for heating the material, said platform having an upper end with means for receivingbthe material, means flexibly supportin said platform for V1 ra tory motion, means for vibrating sai platform for causing the material to progress down said inclined platform while being heated, said platform also being slightly inclined laterally of the first-mentioned direction of inclination for causing molten material to flow laterally on the platform, and an outlet opening at the lateral side of said platform for discharging said molten material.

14. The furnace of claim 13 wherein said platform is slightly crowned along the first-mentioned direction of inclination with said slight lateral inclination extending in both lateral directions, and a said outlet opening is provided at each lateral side of said platform.

15. A continuous furnace for controlled heating of materials to any predetermined temperature, comprising, an inclined platform of a refractory substance forming a hearth for supporting the material to be heated, heating means positioned immediately above substantially the entire said platform for heating the material, said platform having an upper end with means for receiving the material, means flexibly supporting said platform for vibratory motion, means for vibrating said platform for causing the material to progress down said inclined platform whilebeing heated, and said platform having a discharge opening at the lower end thereof for allowing the exit from the furnace of any material remaining on the platform at that point.

16. A continuous furnace for controlled heating of materials to any predetermined temperature, comprising, an inclined platform of a refractory substance forming a hearth for supporting material to be heated, heating means positioned immediately above substantially the entire said platform for heating the material, said platform having an upper end with means for receiving the material, means flexibly supporting said platform for vibratory motion including a metal housing surrounding the exterior of and supporting the refractory material, a plurality of pliable means mounted on and supporting said housing, and means for vibrating said platform for causing the material to progress down said inclined platform while being heated.

17. A continuous furnace for controlled heating of mixed bulk of materials having at least two different melting temperatures, comprising, an inclined platform of a refractory substance forming a hearth for supporting the materials to be heated, heating means positioned immediately above substantially the entire said platform for heating the materials to a preselected temperature, said platform having an upper end with means for receiving the materials, means flexibly supporting said platform for vibratory motion, means for vibrating said platform for causing the material to progress down said inclined platform while being heated, the rate of progression of such materials and said heating to a preselected temperature causing a portion of such materials to melt and flow down the platform, means for collecting and removing said melted material from said furnace, and means for conveying the unmelted portion of such materials passed said collecting means and out of said furnace. 

